Antibody modulating the differentiation and function of dendritic cells via binding intercellular adhesion molecule-1 and use thereof

ABSTRACT

The present invention relates to an antibody binding to human intercellular adhesion molecule-1 (ICAM-1) where the antibody is able to modulate the differentiation status of dendritic cells and prolong the graft survival. In addition, the present invention provides a pharmaceutical composition comprising the antibody, and method of using them for the treatment of disease.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to and the benefit of U.S. Ser.No. 61/087,265, filed Aug. 8, 2008 with United States Patent andTrademark Office which is hereby incorporated by reference for allpurposes as if fully set forth herein.

REFERENCE TO A SEQUENCE LISTING

This application includes a Sequence Listing provided in ASCII text filenamed “SEQLIST.txt” which is of size 2340 bytes and created on Mar. 24,2009, which is hereby incorporated by reference in its entirety for allpurposes.

FIELD OF THE INVENTION

The present invention provides, among other things, antibodies bindingto human intercellular adhesion molecule 1 (ICAM-1). Preferredantibodies are able to modulate the differentiation and function ofdendritic cells and prolong the graft survival. Pharmaceuticalcomposition comprising the antibodies, and methods of using them for thetreatment of disease are also provided.

BACKGROUND OF INVENTION

ICAM-1 is a 90 kDa type I cell surface glycoprotein composed of fiveextracellular immunoglobulin superfamily domains referred to as domains1 through 5 and numbered from N to C-terminus, a transmembrane regionand an intracellular region (Cell. 1990, 61:243-54). ICAM-1 mediatesleukocyte/leukocyte interaction such as interaction between T cells andantigen presenting cells. It also mediates leukocyte extravasation intotissue during inflammatory processes (Transplantation. 1999,67:729-736). In vitro study showed that antibodies interfering theICAM-1/leukocyte function antigen-1 (LFA-1) interaction are able toinhibit T cell adhesion to endothelial cells and T cell activation alsocould be significantly reduced in a mixed lymphocyte reaction by theseantibodies (Proc. Natl. Acad. Sci. USA. 1988, 85:3095-3099). In monkeystudies using murine monoclonal antibodies against human ICAM-1, R6-5-D6(enlimomab), renal allograft survival has been prolonged and T cellinfiltration in the graft was decreased compared with controls (J.Immunol. 1990, 144:4604-4612). Enlimomab also had been proved to bebeneficial in depressing disease activity in patient with rheumatoidarthritis (Arthritis Rheum. 1994, 37:992-999; J. Rheumatol. 1996,23:1338-1344). However, enlimomab induction therapy after renaltransplantation in a randomized multicenter study was not able to reducethe rate of acute rejection or the risk of delayed onset of graftfunction (Transplantation 1999, 67:729-736). Moreover, clinical trial inacute ischemic stroke patient revealed that anti-ICAM-1 therapy withenlimomab was not an effective and indeed significantly worsen strokeoutcome and induced more adverse effect, primarily infections and fevercompared with placebo (Neurology 2001, 57:1428-1434). The enlimomabfunctions by blocking the adhesion of T cells as wells as neutrophils tothe vascular endothelial cells and thus it has been suggested thatinterfering with neutrophil emigration potentially increases thesusceptibility to infection (J. Immunol. 1999, 162:2352-2357).

Dendritic cells (DCs) are highly specialized antigen-presenting cellsthat integrate a variety of immune response (Nature 1998, 382:245-252),and include a heterogeneous family of professional antigen presentingcells involved in initiation of immunity and immunologic tolerance.Until now, immature DCs were believed to induce T-cell anergy, whereasDCs transformed into mature DCs by activation stimuli such aslipopolysaccharide (LPS) were thought to induce primary T cell response(Blood 2006, 108:1435-1440). Furthermore, semimature DCs with adistinctive cytokine production profile might be endowed withtolerogenic functions (Blood 2006, 108:1435-1440).

ICAM-1 is expressed in dendritic cells in high level. Until now,however, ICAM-1 in dendritic cells has been considered to serves as asimple adhesion molecule for LFA-1 binding during T cell-DC interaction.

SUMMARY OF THE INVENTION

One object of the present invention, among others, is to provide anantibody binding to human intercellular adhesion molecule 1 (ICAM-1)where the antibody is able to modulate the differentiation and functionof dendritic cells and prolong the graft survival. In addition, thepresent invention provides a pharmaceutical composition comprising theantibody, and method of using them for the treatment of disease.

More particularly, the present invention provides an anti-human ICAM-1antibody that suppresses rejection of transplanted cells or organs, orsuppresses graft versus host disease by transplanted hematopoieticcells. The invention further provides such an antibody capable ofbinding domain 1 of human ICAM-1 but not blocking the interactionbetween ICAM-1 and its ligand, LFA-1.

The invention further provides a method for producing the material, andit provides cells producing the antibody or its fragment. The inventionalso includes the hybridoma cell, and the antibody produced by thehybridoma cell, obtained by the method.

The present invention also includes a pharmaceutical composition forsuppressing rejection of transplanted cells or organs. Thepharmaceutical composition is comprised of an immunosuppressive agentselected from the group consisting of: an antibody capable of bindingICAM-1 but not inhibiting the interaction of ICAM-1 and LFA-1; and afragment of an antibody, the fragment being capable of binding ICAM-1but not inhibiting the interaction of ICAM-1 and LFA.

Further, the present invention also provides a method for suppressingthe rejection of transplanted cells or organs, or suppresses graftversus host disease by transplanted hematopoietic cells using animmunosuppressive agent, which is selected from the group consisting ofantibody or antibody fragments. The antibody or the antibody fragment ispreferably selected from the group consisting of monoclonal andpolyclonal antibodies, and more preferably it is a human or animal(i.e., non-human) antibody.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention, and many of the attendantadvantages thereof, will be readily apparent as the same becomes betterunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawing, wherein:

FIG. 1 shows a photograph of the reactivity of MD-2 and R6-5-D6monoclonal antibodies on the surface of human ICAM-1-transfected HEK293Tcells using single color flow cytometry.

FIG. 2 shows a photograph of the reactivity of MD-2 and R6-5-D6antibodies on the HEK293T cells transfected with h1m2345 and h12m345ICAM-1 mutants

FIG. 3 shows the result of thymidine uptake after mixed lymphocytereaction in the presence of MD-2 or R6-5-D6 antibody.

FIG. 4 shows a photograph of the reactivity of R6-5-D6 antibody on thehuman ICAM-1-positive DU145 cells after pre-incubation with MD-2 orR6-5-D6 antibody.

FIGS. 5A and 5B shows the expression level of various molecules on thesurface of dendritic cells (A) and cytokine concentration in the culturemedia of dendritic cells (B) after treatment of indicated antibodies.

FIGS. 6A and B shows the kinetics of the generation of CD45⁺ humanleukocytes (A) and CD3⁺ human T cells (B) in peripheral blood ofhumanized mice.

FIG. 7 shows the peripheral blood glucose level in humanized mice inwhich diabetes was induced by streptozotocin and then rat islets weretransplanted.

FIG. 8 shows the photograph of hematoxylin and eosin (H&E) staining andimmunohistochemical staining for insulin in islet-grafted kidneysextracted from each mouse treated with indicated antibodies.

DETAILED DESCRIPTION

The present invention is further explained in more detail with referenceto the following examples. These examples, however, should not beinterpreted as limiting the scope of the present invention in anymanner.

The present invention relates to a mouse anti-human ICAM-1 monoclonalantibody, MD-2 and fragments of MD-2 capable of inhibiting immuneresponse. More particularly, the present invention relates to anti-humanICAM-1 antibody that suppresses rejection of transplanted cells ororgans, or suppresses graft versus host disease by transplantedhematopoietic cells.

The invention further provides an antibody capable of binding domain 1of human ICAM-1 but not blocking the interaction between ICAM-1 and itsligand, LFA-1. The invention also includes a hybridoma cell capable ofproducing such an antibody.

The invention is further directed to a method for producing thematerial, and it provides cells producing the antibody or its fragment.The method of producing antibody or its fragment includes the step of(a) immunization an animal with human ICAM-1 protein or proteinfragments or a cell expressing human ICAM-1, (b) extracting splenocytesfrom the immunized animal, (c) fusing the spleen cells of the animalwith a myeloma cell line, and (d) screening the hybridoma cells andselecting the desired hybridoma cell that is capable of modulating thedifferentiation and function of dendritic cells as wells as suppressingthe rejection of transplanted organs but not inhibiting the interactionbetween ICAM-1 and LFA-1. The material can be obtained by in vitroculture or injection into the animals of cells producing the materials.The material can be obtained from the ascites of animals in which thecells producing the materials are intraperitoneally injected. Thematerials can be purified from the culture supernatant or ascites by ionexchange chromatography or affinity column chromatography.

The invention also includes the hybridoma cell, and the antibodyproduced by the hybridoma cell, obtained by the method.

The present invention also includes to a pharmaceutical composition forsuppressing rejection of transplanted cells or organs. Thepharmaceutical composition is comprised of an immunosuppressive agentselected from the group consisting of: an antibody capable of bindingICAM-1 but not inhibiting the interaction of ICAM-1 and LFA-1; and afragment of an antibody, the fragment being capable of binding ICAM-1but not inhibiting the interaction of ICAM-1 and LFA. Administration ofthe antibody or its fragment according to the invention can be carriedout using any of the accepted modes of administration of pharmaceuticalcompositions.

Further, the present invention also relates to the method forsuppressing the rejection of transplanted cells or organs, which usesmaterials selected from the group consisting of antibody or antibodyfragments. The antibody or the antibody fragment is preferably selectedfrom the group consisting of monoclonal and polyclonal antibodies, andmore preferably it is a human or animal antibody.

The invention also provides methods of detecting ICAM-1 using theantibodies to ICAM-1 disclosed herein. Such detection is useful becauseICAM-1 is a marker of inflammation among other disease processes.Antibodies to ICAM-1 can also be sold commercially as research reagentsfor detecting ICAM-1.

A humanized antibody is an antibody having complementary determiningregions (CDRs) from a donor antibody and variable region framework andconstant regions from a human antibody. CDRs are typically as defined byKabat but can alternatively be as defined by Chothia or a composite ofKabat and Chothia definitions (e.g., any residue within a Kabat and/orChothia CDR). Thus, typically a humanized antibody comprises (i) a lightchain comprising three CDRs from a mouse antibody, e.g., MD-2, avariable region framework from a human antibody (which can be, forexample, from a mature human antibody, a human germline sequence, acomposite of two or more human antibody sequences, or a consensus ofhuman antibody sequences), and a human constant region, and (ii) a heavychain comprising three CDRs from a mouse antibody, e.g., MD-2, avariable region framework from a human antibody and a human constantregion. The heavy and/or light chain variable region frameworks can alsoinclude backmutations at a few (usually fewer than 1, 2, 3, 4, 5 or 10)selected positions per chain in which a human residue is replaced withthe residue occupying the corresponding position of the mouse antibody(see, Queen et al., U.S. Pat. Nos. 5,530,101 and 5,585,089).Specifically, the amino acids to be replaced in the framework aregenerally chosen on the basis of their ability to interact with theCDRs. For example, the replaced amino acids can be adjacent to a CDR inthe donor antibody sequence or within 4-6 angstroms of a CDR in thehumanized antibody as measured in 3-dimensional space.

Substitution of one or more CDR residues or omission of one or more CDRsis also possible provided sufficient CDR residues are retained forretention of binding to ICAM-1. Numerous antibodies have been describedin the scientific literature in which one or two CDRs can be dispensedwith for binding. Padlan et al., FASEB Journal 9: 133-139 (1995); Vajdoset al (Journal of Molecular Biology, vol. 320, pp. 415-428 (2002);Iwahashi et al., Mol. Immunol. 36:1079-1091, (1999); Tamura et al,Journal of Immunology, 2000, 164:1432-1441 (2000). The substitution ofcertain regions within CDRs is based on the same principle as omittingdispensable CDRs, namely that only a small subset of CDR residues, theSDR's, actually contact antigen.

CDR residues not contacting antigen can be identified based on previousstudies (for example residues H60-H65 in CDRH2 are often not required),from regions of Kabat CDRs lying outside Chothia CDRs, by molecularmodeling and/or empirically. If a CDR or residue(s) thereof is omitted,it is usually substituted with an amino acid occupying the correspondingposition in human acceptor sequence supplying the variable regionframework sequences. The number of such substitutions to includereflects a balance of competing considerations Such substitutions arepotentially advantageous in decreasing the number of mouse amino acidsin a humanized antibody and consequently decreasing potentialimmunogenicity. However, substitutions can also cause changes ofaffinity, and significant reductions in affinity are preferably avoided.Positions for substitution within CDRs and amino acids to substitute canalso be selected empirically. Empirical substitutions can beconservative or non-conservative substitutions. However, in generalempirical substitutions do not have the advantage of mouse to humansubstitutions in reducing immunogenicity. Empirical substitutions canincrease or decrease affinity of the resulting humanized antibody.

In general humanized antibodies with satisfactory binding affinity toICAM-1 and lack of substantial immunogenicity can be obtained byindividual screening of a few variants made according to the aboveprinciples above. However, very large numbers of variants can besimultaneously screened using a display selection method such as phagedisplay (see (Dower et al., WO91/17271; McCafferty et al., WO92/001047;and Winter, WO92/20791).

A chimeric antibody is an antibody in which the variable region of amouse from heavy and light chains (or other rodent) antibody is combinedwith the heavy and light chain constant region of a human antibody;their construction by means of genetic engineering is well-known. Suchantibodies retain the binding specificity of the mouse antibody, whilebeing about two-thirds human. The proportion of nonhuman sequencepresent in mouse, chimeric and humanized antibodies suggests that theimmunogenicity of chimeric antibodies is intermediate between mouse andhumanized antibodies.

Usually humanized and chimeric antibodies are of the IgG1, IgG2, IgG3 orIgG4 isotype with a kappa light chain.

The monoclonal antibodies (mAbs) may be of animal (e.g., mouse, rat,hamster or chicken) origin, or they may be genetically engineered.Rodent mAbs are made by standard methods well-known in the art,comprising multiple immunization with ICAM-1 in appropriate adjuvanti.p., i.v., or into the footpad, followed by extraction of spleen orlymph node cells and fusion with a suitable immortalized cell line, andthen selection for hybridomas that produce antibody binding to ICAM-1,e.g., see under Examples. Human antibodies can also be made by phagedisplay (see, e.g., Dower et al., WO91/17271; McCafferty et al.,WO92/001047; Winter, WO92/20791; and Winter, FEBS Lett. 23:92, 1998) orby using transgenic mice (see, e.g., Lonberg et al., WO93/12227;Kucherlapati WO91/10741) Chimeric and humanized mAbs are preferredembodiments of the invention.

Antibodies are very large, complex molecules (molecular weight of˜150,000 or about 1320 amino acids) with intricate internal structure. Anatural antibody molecule contains two identical pairs of polypeptidechains, each pair having one light chain and one heavy chain. Each lightchain and heavy chain in turn consists of two regions: a variable (“V”)region involved in binding the target antigen, and a constant (“C”)region that interacts with other components of the immune system. Thelight and heavy chain variable regions fold up together in 3-dimensionalspace to form a variable region that binds the antigen (for example, areceptor on the surface of a cell). Within each light or heavy chainvariable region, there are three short segments (averaging 10 aminoacids in length) called the complementarity determining regions(“CDRs”). The six CDRs in an antibody variable domain (three from thelight chain and three from the heavy chain) fold up together in 3-Dspace to form the actual antibody binding site which locks onto thetarget antigen. The position and length of the CDRs have been preciselydefined. Kabat, E. et al., Sequences of Proteins of ImmunologicalInterest, U.S. Department of Health and Human Services, 1983, 1987. Thepart of a variable region not contained in the CDRs is called theframework, which forms the environment for the CDRs.

Antibodies can bind specifically to a particular target protein; thatis, bind the target protein preferentially in a mixture of differentproteins including the target protein. Specific binding also usuallymeans a dissociation constant (KD) that is less than about 10⁻⁶ M; 10⁻⁷M, 10⁻⁸ M or 10⁻⁹ M.

Native mAbs of the invention may be produced from their hybridomas.Genetically engineered mAbs, e.g., chimeric or humanized mAbs, may beexpressed by a variety of art-known methods. For example, genes encodingtheir light and heavy chain V regions may be synthesized fromoverlapping oligonucleotides and inserted together with available Cregions into expression vectors (e.g., commercially available fromInvitrogen) that provide the necessary regulatory regions, e.g.,promoters, enhancers, poly A sites, etc. Use of the CMVpromoter-enhancer is preferred. The expression vectors may then betransfected using various well-known methods such as lipofection orelectroporation into a variety of mammalian cell lines such as CHO ornon-producing myelomas including Sp2/0 and NS0, and cells expressing theantibodies were selected by appropriate antibiotic selection.

Once expressed, the mAbs or other antibodies of the invention may bepurified according to standard procedures of the art such asmicrofiltration, ultrafiltration, protein A or G affinitychromatography, size exclusion chromatography, anion exchangechromatography, cation exchange chromatography and/or other forms ofaffinity chromatography based on organic dyes or the like. Substantiallypure antibodies of at least about 50, 90 or 95% homogeneity arepreferred, and 98% or 99% or more homogeneity most preferred, forpharmaceutical uses.

The terms “isolated” and “purified” refer to a material that issubstantially or essentially removed from or concentrated in its naturalenvironment and/or undesired contaminants. For example, an isolatedantibody is separated from other antibodies directed to other antigensand from other biological materials (e.g., other nucleic acids,proteins, lipids, cellular components) with which it is naturallyassociated. The antibodies of the invention also include bindingfragments of antibodies such as Fv, Fab and F(ab′)₂; bifunctional hybridantibodies (e.g., Lanzavecchia et al., Eur. J. Immunol. 17:105, 1987),single-chain antibodies (Huston et al., Proc. Natl. Acad. Sci. USA85:5879, 1988; Bird et al., Science 242:423, 1988); and antibodies withaltered constant regions (e.g., U.S. Pat. No. 5,624,821)

In a preferred embodiment, the present invention provides apharmaceutical formulation comprising the antibodies described herein.That is, the antibodies can be used in the manufacture of a medicamentfor treatment of disease. Pharmaceutical formulations (i.e.,medicaments) of the antibodies contain the mAb in a physiologicallyacceptable carrier, optionally with excipients or stabilizers, in theform of lyophilized or aqueous solutions. Acceptable carriers,excipients or stabilizers are nontoxic to recipients at the dosages andconcentrations employed, and include buffers such as phosphate, citrate,or acetate at a pH typically of 5.0 to 8.0, most often 6.0 to 7.0; saltssuch as sodium chloride, potassium chloride, etc. to make isotonic;antioxidants, preservatives, low molecular weight polypeptides,proteins, hydrophilic polymers such as polysorbate 80, amino acids,carbohydrates, chelating agents, sugars, and other standard ingredientsknown to those skilled in the art.

The mAb is typically present at a concentration of 1-100 mg/ml, e.g., 10mg/ml.

In another preferred embodiment, the invention provides a method oftreating a patient, typically a human, with a disease using ananti-ICAM-1 mAb in a pharmaceutical formulation. The mAb prepared in apharmaceutical formulation can be administered to a patient by anysuitable route, especially parentally by intravenous infusion or bolusinjection, intramuscularly or subcutaneously. Intravenous infusion canbe given over as little as 15 minutes, but more often for 30 minutes, orover 1, 2 or even 3 hours. The mAb can also be injected directly intothe site of disease (e.g., a tumor), or encapsulated into carryingagents such as liposomes. The dose given will be sufficient to alleviatethe condition being treated (“therapeutically effective dose”) and islikely to be 0.1 to 5 mg/kg body weight, for example 1, 2, 3 or 4 mg/kg,but may be as high as 10 mg/kg or even 15 or 20 mg/kg. A fixed unit dosemay also be given, for example, 50, 100, 200, 500 or 1000 mg, or thedose may be based on the patient's surface area, e.g., 100 mg/m².

The mAb can be administered daily, weekly, biweekly, every other week,monthly or at some other interval, depending, e.g. on the half-life ofthe mAb, for 1 week, 2 weeks, 4 weeks, 8 weeks, 3-6 months or longer.Repeated courses of treatment are also possible, as is chronicadministration. A regime of a dosage and intervals of administrationthat alleviates or at least partially arrests the symptoms of thedisease (biochemical, histologic and/or clinical), including itscomplications and intermediate pathological phenotypes in development ofthe disease is referred to as a therapeutically effective regime.

ICAM-1 is a well-known human protein, the amino acid sequence of whichis provided by Simmons et al., Nature 331, 624-627 (1988) and GenBankaccession 06990.1. LFA is a heterodimer of CD11a and CD18. The aminoacid sequence of human CD11a is provided by Larson et al., J. Cell.Biol. 108, 703-712 (1989) and GenBank Y00796.1. The amino acid sequenceof human CD18 is provided by Kishimoto et al., Cell 48, 681-690 (1987)and GenBank M15395.1

The present invention is further explained in more detail with referenceto the following examples. These examples, however, should not beinterpreted as limiting the scope of the present invention in anymanner.

Example 1 The Isolation of Hybridoma Cells Capable of ProducingAnti-Human ICAM-1 Monoclonal Antibodies

To produce ICAM-1/Fc proteins, mRNAs were extracted from PHA-activatedhuman peripheral blood mononuclear cells and the cDNA fragmentscorresponding to the leader gene segments and extracellular domains ofhuman ICAM-1 were amplified by polymerase chain reaction (PCR). Afragment encoding the extracellular domain of ICAM-1 was cloned with theintroduction of NheI and EcoRI sites at the 5′ and 3′ ends,respectively. To form the fusion construct of human ICAM-1 and human IgGFc, this fragment was ligated into EcoRI and XhoI-digested plasmid thatencoded for the hinge CH2 and CH3 domains of hIgG1. The HEK293T cellswere transiently transfected with the plasmids, and ICAM-1/Fc proteinswere purified form culture supernatants using protein G column.

Balb/c mice were intraperitoneally immunized with 100 μg of ICAM-1/Fcproteins emulsified in complete Freund's adjuvant and then subsequenttwice immunizations were with 100 μg of ICAM-1/Fc proteins emulsified inincomplete Freund's adjuvant at two weeks interval. Two weeks later,immunized mice were boosted with 100 μg of ICAM-1/Fc proteins. Thespleen of Balb/c mice was removed 3 days after the last administrationto prepare the spleen cell suspension. Monoclonal antibodies wereproduced by fusing the spleen cells of Balb/c immunized with humanICAM-1/Fc with SP2/0-Ag14 mouse myeloma cells resistant to 9-azaguanine.Cell fusion method followed Koeler and Milstein method (Koeler &Milstein Nature, 1975, 256, 495-497). 10⁸ spleen cells were fused with10⁷ myeloma cells using 50% polyethylene glycol 4000. The cells werewashed and resuspended in Dulbeco's modified Eagle's medium (DMEM)containing 20% fetal bovine serum (FBS), 100 μM hypoxanthine, 0.44 μMaminopterin and 16 μM thymidine (HAT media). The cells were introducedto four 96-well plates and cultured at 37° C. in a 5% CO₂ incubator.

When colonies were formed after two weeks, the supernatant were screenedusing human ICAM-1-transfected HEK 293T cells. Both ICAM-1-transfectedand wild type HEK293T cells were stained with culture supernatant andcells producing supernatant reactive against ICAM-1-transfected 293Tcells but not wild type 293T cells were selected. Cells taken from thepositive wells were subcloned 0.5 cell per well by limiting dilutionassay to produce stable hybridoma clone with high reactivity ofantibody.

This experiment resulted in the identification and cloning of threeseparate hybridoma lines which produce anti-ICAM-1 monoclonalantibodies. One of these hybridoma lines produced IgG1 antibody with akappa light chain and was given the designation MD-2. The hybridomanamed for MD-2 was deposited at Cancer Research Institute located onSeoul National University, College of Medicine, 28 Yongon-dong,Chongno-Gu, Seould, 110-744, Republic of Korea on Dec. 24, 2008, andreceived as an accession number of KCLRF-BP-00198. This deposit will bemaintained at an authorized depository and replaced in the event ofmutation, nonviability or destruction for a period of at least fiveyears after the most recent request for release of a sample was receivedby the depository, for a period of at least thirty years after the dateof the deposit, or during the enforceable life of the related patent,whichever period is longest. All restrictions on the availability to thepublic of this cell line will be irrevocably removed upon the issuanceof a patent from the application.

As shown in FIG. 1, ICAM-1-transfected 293T cells were positivelystained by MD-2 antibody as well as a known anti-human ICAM-1 antibody,R6-5-D6, while either antibody was not reactive against wild typeuntransfectant.

Once an exemplary antibody has been identified (e.g., MD-2) otherantibodies binding to the same or overlapping epitope on ICAM-1 can beidentified by a competitive binding assay. Two antibodies bind to thesame or overlapping epitope if each competitively inhibits (blocks)binding of the other to the antigen. That is, a 1×, 5×, 10×, 20× or 100×excess of one antibody inhibits binding of the other by at least 50% butpreferably 75%, 90% or even 99% as measured in a competitive bindingassay (see, e.g., Junghans et al., Cancer Res. 50:1495, 1990). Thecompetitive binding assay can be performed on intact ICAM-1, theextracellular region thereof including five immunoglobulin-like domains,or on domain 1 separated from the other immunoglobulin-like domains.Alternatively, the method of Jespers et al., Biotechnology 12:899, 1994,which is incorporated herein by reference, may be used to guide theselection of mAbs having the same epitope and therefore similarproperties to the archtypal mAb, MD-2. Using phage display, first theheavy chain of the archtypal antibody is paired with a repertoire of(preferably human) light chains to select an HGF-binding mAb, and thenthe new light chain is paired with a repertoire of (preferably human)heavy chains to select a (preferably human) ICAM-1-binding mAb havingthe same epitope as the archtypal mAb.

Variants of MD-2 and its humanized and chimeric forms can also be madeby substitution of amino acids, particularly at variable regionframework positions. Such substitutions can be conservative ornonconservative. For purposes of classifying amino acids substitutionsas conservative or nonconservative, amino acids may be grouped asfollows: Group I (hydrophobic sidechains): Met, Ala, Val, Leu, Ile;Group II (neutral hydrophilic side chains): Cys, Ser, Thr; Group III(acidic side chains): Asp, Glu; Group IV (basic side chains): Asn, Gln,His, Lys, Arg; Group V (residues influencing chain orientation): Gly,Pro; and Group VI (aromatic side chains):Trp, Tyr, Phe. Conservativesubstitutions are those that involve substitutions between amino acidsin the same group. Variants can be screened for binding to ICAM-1,particularly the first domain thereof, optionally in competition withthe MD-2 antibody. The heavy and light chains of a variant preferablyshow at least 90, or 95% amino acid sequence identity with a referenceantibody, such as MD-2, particularly in the CDR regions. Sequenceidentity is determined by comparing heavy or light chain variableregions maximally aligned with heavy or light chain variable regions ofa reference antibody by Kabat numbering not counting gaps.

Example 2 Mapping of Antibody Binding Domain

ICAM-1 has a structure composed of five immunoglobulin-like (Ig-like)domains, a transmembrane domain and a cytoplasmic domain (Cell. 1992,68:71-81). In order to localize the site of MD-2 binding to a particularICAM-1 Ig-like domain, two kinds of chimeric cDNAs were made that codefor human domain 1/murine domains 2-5 including murine transmembrane andcytoplasmic domains (h1m2345) and for human domains 1-2/murine domains3-5 (h12m345), using human and murine ICAM-1 cDNA clones. Theoverlapping PCR technique was used to construct these chimeric mutants.The cDNA containing human domain 1 (h1) was first amplified using theprimers as follows: 5′ primer GAA TTC ATG GCT CCC AGC AGC CCC CGG CCCGCG CT (SEQ ID NO: 1); 3′ primer AGG TCT CAG CTC CAC CCG TTC TGG AGT CCAGTA CAC GGT GAG GAA G (SEQ ID NO: 2). Primers for the generation ofmurine domains 2-5, a transmembrane domain and a cytoplasmic domain(m2345) were as follows: 5′ primer, CTG GAC TCC AGA ACG G GTG GAG CTGAGA CCT CTG CCA GCC TGG CAG (SEQ ID NO: 3); 3′ primer GGA TCC GGG AGGTGG GGC TTG TCC CTT GAG TTT TAT GGC (SEQ ID NO: 4). These two kinds ofcDNA were mixed and re-amplified using SEQ ID NO: 1 and SEQ ID NO: 4primers and the final product (h1m2345) was cloned in pcDNA3.1 vector.The mutant that code h12m345 was also cloned in the way similar to thatfor h1m2345 using the following primers: 5′ primer for h12, GAA TTC ATGGCT CCC AGC AGC CCC CGG CCC GCG CT (SEQ ID NO:5); 3′ primer for h12, GGTAGC TGG AAG ATC AAA GGT CTG GAG CTG GTA GGG GGC CGA GGT (SEQ ID NO:6);5′ primer for m345, CAG CTC CAG ACC TTT GAT CTT CCA GCT ACC ATC CCA AAGCTC GAC ACC (SEQ ID NO:7); 3′ primer for m345, GGA TCC GGG AGG TGG GGCTTG TCC CTT GAG TTT TAT GGC (SEQ ID NO:8).

The entire construct were sequenced to confirm that the correctedjunctions had been obtained and then plasmid DNA were transfected toHEK293T cells using calcium phosphate precipitation method. Afterincubation of HEK293T cells with coprecipitates of calcium phosphate andplasmid DNA for 16-20 hrs, media were replaced with 10 ml of freshsolution and the cells were incubated for another 24 hours. Then,transfectant was stained with MD-2 or R6-5-D6 antibody in ice. Afterincubation for 30 min, cells were washed three times in phosphatebuffered saline (PBS) with 5% fetal calf serum and 0.1% azide andincubated for 30 min with FITC-conjugated goat anti-mouse Ig antibody(2^(nd) Ab). After a further three washes, flow cytometric analysis wasperformed to test for their ability to react with each antibody (FIG.2). As the negative control, cells stained with only 2^(nd) Ab wereused. As shown in FIG. 2, full human ICAM-1 transfectant was positivelystained with both MD-2 and R6-5-D6 antibodies, whereas either antibodieswere not reactive with full mouse ICAM-1 transfectant, indicating theseanti-human ICAM-1 antibodies are not cross-reactive with mouse ICAM-1.In the case of chimeric mutant, MD-2 antibody reacted with both chimera,h1m2345 and h12m345, while R6-5-D6 antibody that had been previouslyassigned to the domain 2 (Cell. 1992, 68:71-81) were reactive only withthe h12m345 chimera. Thus, all these results indicated that MD-2antibody is specific for epitope on domain 1 and R6-5-D6 antibody map todomain 2.

Example 3 Effect of Anti-ICAM-1 Antibody in Mixed Lymphocyte Reaction

Although the LFA-1-binding site is located in domain of ICAM-1, domain 2had been known to play an essential role in the confirmation of domain 1(Cell. 1992, 68:71-81). Thus, some of antibodies blocking theinteraction between LFA-1 and ICAM-1 mapped to the domain 1, whereasother antibodies that map the domain 2 such as R6-5-D6 antibody are alsoable to inhibit this interaction (Cell. 1992, 68:71-81). We alsoinvestigated whether LFA-1 and ICAM-1 interaction could be affected byMD-2 antibody.

When lymphocytes from two unrelated persons are cultured in each other'spresence, proliferation of lymphocytes are observed and this mixedlymphocyte reaction (MLR) has been known to dependent on theICAM-1/LFA-1 interaction (Proc. Natl. Acad. Sci. USA. 1988,85:3095-3099). Thus, MLR assay was performed to assess whetheranti-ICAM-1 antibody, MD-2 is able to interfere with LFA-1 adhesion toICAM-1. Fresh blood cells were obtained from two unrelated donors andperipheral blood mononuclear cells were collected after overly onFicoll-hypaque (Pharmacia, Uppsala, Sweden) and centrifugation at 2,000rpm for 20 minutes and re-suspended in DMEM with 10% fetal bovine serum.CD4⁺ T cells were purified from one donor using magnetic activated cellsorting (MACS) system described in EXAMPLE 5. Cell from the other donorwere irradiated with 2000 cGy using cobalt radiation source. Then aftermixing cells from each donor, mixed cells were plated in flat-bottomed,96 well tissue culture plates at 1×10⁶ cells/well and cultured inpresence or absence of anti-ICAM-1 antibodies (20 μg/ml). The cultureswere pulsed with [³H]thymidine (0.5 μCi/well) after 3 days, harvestedonto glass fiber filters 16 hours later, and then counted on a liquidscintillation β counters. As shown in FIG. 3, anti-ICAM-1 blockingantibody, R6-5-D6 suppressed MLR, while the proliferation of culturedcells was not affected by MD-2 antibody. These results suggest that MD-2antibody have no activity to block the interaction of ICAM-1 and LFA-1.

Example 4 Comparison of Binding Epitope of MD-2 and R6-5-D6 Antibodies

The results from Example 2 suggest that binding epitope of MD-2 antibodymay be different form that of R6-5-D6. To confirm this suggestion,cross-blocking study in which the biding of one antibody in turn iscompeted for by the other antibody (Cell. 1992, 68:71-81) was performed.10, 1, or 0.1 μg of MD-2 or R6-5-D6 antibody was preincubated withICAM-1-positive DU145 cells for 30 min on ice and washed twice prior toincubation with 1 μg of FITC-conjugated R6-5-D6 antibody. Control usedwas omission of competing antibodies from the assay. Cells were washedtwice and analyzed using flow cytometry. As shown in FIG. 4, Binding ofFITC-conjugated R6-5-D6 antibody was inhibited by preincubation withunconjugated R6-5-D6 antibody in a dose-dependent manner. Whereas thepreincubation of DU145 cells with MD-2 antibody had no effect on thebinding of R6-5-D6 antibody, indicating that the binding epitope of MD-2antibody is different from that of R6-5-D6 antibody.

Example 5 Effect of Anti-ICAM-1 Antibody in the Differentiation ofMonocyte-Derived Dendritic Cells

Peripheral blood mononuclear cells were isolated from healthy donorblood by Ficoll-hypaque density-gradient centrifugation. After washingtwice with PBS, cells were re-suspended in MACS buffer at theconcentration of 1×10⁸ cells/ml and then incubated with anti-CD14magnetic bead (20 μl/10⁷ cells; Miltenyi Biotec, Bergisch Gladbach,Germany) in ice for 15 minutes, followed by magnetic separation usingMACS (Milteny-Biotech). Purified CD14⁺ monocytes were re-suspended inRPMI with 10% FBS and were cultured for 6 days withgranulocytes-macrophage colony stimulating factor (GM-CSF, 1000 U/ml)and IL-4 (1000 U/ml). The culture was supplemented with antibody (10mg/ml) on day 0 and day 3 and LPS was added to the culture medium on day6. One day later, cultured cells were harvested and expression of MHCclass I, MHC class II, CD80, CD86, CD40, and CD83 was examined by flowcytometry. ELISA was also done to measure the amount of IL-6, IL-10,IL-12p70, IFN-γ and TNF-α in culture media. When CD14⁺ monocytes werecultured in the presence of GM-CSF and IL-4, they are able todifferentiate into the immature DCs and LPS treatment induces thematuration of immature DCs. The mean fluorescence intensity (MFI) ofindicated antigens and the cytokine concentration in each culture mediawas displayed in FIG. 5B. As expected, LPS treatment in immature DCenhanced the expression of MHC class I, MHC class II, CD80, CD86, andCD40 and cytokine production. Up-regulation of the surface expression ofthese molecules and cytokine production in DCs by LPS stimulation wasnot suppressed by pretreatment of anti-ICAM-1 blocking antibody,R6-5-D6. Unlike R6-5-D6 antibody, however, pretreatment of MD-2 antibodyprior to LPS stimulation significantly suppressed the up-regulation ofsurface molecule expression and cytokine production in the DCs,indicating that MD-2 antibody is able to inhibit the maturation ofmonocyte-derived DCs.

Example 6 Generation of Humanized Mice

To investigate the in vivo effect of anti-ICAM-1 antibodies, humanizedmice were generated by engraftment of human hematopoietic stem cells inimmunodeficient mice according the procedure by Ito, M. et al., Blood.2002, 100:3175-82.

Umbilical cord blood cells were collected during normal full-termdelivers and mononuclear cells were separated by Ficoll-hypaquecentrifugation. Separated mononuclear cell were suspended at 3.3×10⁸cells/ml in PBS containing 5% FBS and 2 mM EDTA and incubated in ice for30 minutes with Fc blocking antibody, followed by incubation in ice for30 minutes with anti-CD34 magnetic beads (Milteny-Biotech). After twicewashing, bead-attached cells were collected by magnetic separation usingMACS. After two rounds of magnetic separation, purity was evaluated byflow cytometry and no less than 95% of the collected cells were CD34⁺.8- to 12-wekk-old NOD.SCID/γc^(null) mice (Central Institute forExperimental Animals, Japan) were irradiated with 240 cGy using cobaltradiation source and 1 day later 1×10⁵ CD34⁺ cells were injected intothe each mouse through the tail vein. Peripheral blood was taken fromthe retro-orbital venous plexus sequentially between weeks 4 and 16after transplantation and stained with anti-human CD45 and anti-humanCD3 antibodies for flow cytometry. FIG. 6 shows the chimeric rates ofhuman cells in the peripheral blood of mice at the indicated weeks aftercell transplantation. Human leukocytes were detected in all mice andmore than 60% of leukocytes in peripheral blood were human CD45⁺ at 11weeks after transplantation (FIG. 6A) and approximately 10% of the humanCD45⁺ cells expressed CD3 at 16 weeks after transplantation (FIG. 6B).

Example 7 Effect of Anti-ICAM-1 Antibody in Suppressing the Rejection ofTransplanted Xenogenic Islet

In order to demonstrate the effect of MD-2 antibody in suppressing thetransplantation rejection, islet xenograft model was used. Humanizedmice were rendered diabetic by twice intraperitoneal injection of 100mg/kg streptozotocin (Sigma, St. Louis, Mo.) dissolved in citratebuffer, pH 4.5 on 2 consecutive days. Blood glucose levels weredetermined using ACCU-CHECK glucometer (Roche, Mannheim, Germany) at 3day after streptozotocin injection and only animals with bloodglucose >250 mg/dl were used as diabetic recipients. Islets fortransplantation were isolated from the Sprague-Dolley rats by stationarycollagenase digestion (0.07% type XI collagenase, Sigma), followed bydiscontinuous Ficoll (Ficoll 400, Pharmacia) density gradient asprevious described (Transplantation. 2000, 69:1567-1571). Afterisolation, crude islet cells were over-night cultured in DMEM with 10%FBS at 37° C. in a 5% CO₂ incubator and then 500 islets weretransplanted into the left renal subcapsular space of each diabetichumanized mouse at 4 day after streptozotocin injection. Anti-ICAM-1antibody (300 μg/mouse) was injected intraperitoneally at 6 and 3 daybefore islet transplantation. Control group of animal receivedirrelevant mouse IgG. Return of blood glucose levels to less than 200mg/dl was used as an indicator of graft function, and a sudden rise tolevels >250 mg/dl on 2 consecutive days was indicative of rejection. Asshown in FIG. 7, mice of control group died or graft were rejectedwithin 3 weeks after islet transplantation, while blood glucose levelwas maintained still in less than 200 mg/dl throughout the follow-upperiod in all mice received MD-2 antibody prior to islet graft.

Mice were sacrificed when they showed a morbid condition and leftnephrectomy specimen was analyzed histologically for evidence of graftrejection. Control mice were sacrificed at day 9, 21 and 44post-grafting, In MD-2 antibody-treated group, mice were sacrificed atday 34, 77 and 87 post-grafting. Nephrectomy specimen from each mice wasfixed in 10% neural formalin, embedded in paraffin and then seriallysectioned in 4 μm thickness for routine hematoxylin-eosin staining orimmunohistochemistry. Staining for insulin utilized a primary goatantiserum to human insulin (DAKO, Carpenteria, Calif.) followed by theanvidin-biotin peroxidase method and diaminobenzidine as substrate. Ascan be seen in FIG. 8, infiltration of mononuclear cells was evident inthe subcapsular area of mice received control antibody andimmunohistochemical staining failed to reveal the viable islet in thesemice. However unlike to control mice, graft survival was still evidentand mononuclear cells infiltrate was not observed in MD-2-treated mice.Moreover, the grafted islets continued to produce insulin. Thus, MD-2treatment prior to transplantation is able to lead the prolongedsurvival of the islet xenografts.

All publications, patents and patent applications cited are hereinincorporated by reference in their entirety for all purposes to the sameextent as if each individual publication, patent and patent applicationwas specifically and individually indicated to be incorporated byreference in its entirety for all purposes.

1. A monoclonal antibody that binds to human intracellular adhesionmolecule 1 (ICAM-1), wherein the antibody is designated MD-2 and isproduced by a hybridoma deposited as accession number KCLRF-BP-00198. 2.A pharmaceutical composition comprising the antibody of claim
 1. 3. Thepharmaceutical composition according to claim 2, wherein the antibody isin isolated form.
 4. A pharmaceutical composition for modulating thedifferentiation of dendritic cells via binding ICAM-1, comprising theantibody according to claim
 1. 5. A pharmaceutical composition forsuppressing refection of transplanted cells or organs, or suppressinggraft versus host disease by transplanted hematopoietic cells,comprising the antibody according to claim
 1. 6. A monoclonal antibodythat binds to human ICAM-1 comprising a heavy chain and a light chain,the heavy chain comprising three CDRs from the heavy chain of anantibody produced by a hybridoma deposited as accession numberKCLRF-BP-00198 and the light chain comprising three CDRs from the lightchain of an antibody produced by a hybridoma deposited as accessionnumber KCLRF-BP-00198.
 7. The antibody according to claim 6, wherein theantibody is a chimeric or humanized antibody.
 8. A pharmaceuticalcomposition comprising the antibody according to claim 6 for suppressingresection of transplanted cells or organs, or suppressing graft versushost disease by transplanted hematopoietic cells.
 9. A pharmaceuticalcomposition comprising a monoclonal antibody that binds to human ICAM-1comprising a heavy chain and a light chain, the heavy chain comprisingthree CDRs from the heavy chain of an antibody produced by a hybridomadeposited as accession number KCLRF-BP-00198 and the light chaincomprising three CDRs from the light chain of an antibody produced by ahybridoma deposited as accession number KCLRF-BP-00198.
 10. Thepharmaceutical composition according to claim 9, wherein the antibody ischimeric antibody or humanized antibody.
 11. A hybridoma producing anantibody, wherein the antibody binds to domain 1 of human intercellularadhesion molecules-1 (ICAM-1), which is deposited as accession numberKCLRF-BP-00198.